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32. T. Kamae, N. Karlsson, T. Mizuno, T. Abe, T. Koi, Astrophys. J. 647, 692 (2006). 33. M. Mori, Astropart. Phys. 31, 341 (2009). Acknowledgments: The Fermi LAT Collaboration acknowledges support from a number of agencies and institutes for both development and the operation of the LAT as well as scientific data analysis. These include NASA and the U.S. Department of Energy (United States); CEA/Irfu and IN2P3/CNRS (France); ASI and INFN (Italy); MEXT, KEK, and JAXA (Japan); and the K. A. Wallenberg Foundation, the Swedish Research Council, and the National Space Board (Sweden). Additional support from INAF in Italy and CNES in France for science analysis during the operations phase is also gratefully acknowledged. Fermi LAT data are available from the Fermi Science Support Center (http://fermi.gsfc.nasa.gov/ssc). Crystalline Inorganic Frameworks with 56-Ring, 64-Ring, and 72-Ring Channels Hsin-Yau Lin, 1 Chih-Yuan Chin, 1 Hui-Lin Huang, 1 Wen-Yen Huang, 1 Ming-Jhe Sie, 1 Li-Hsun Huang, 1 Yuan-Han Lee, 1 Chia-Her Lin, 2 Kwang-Hwa Lii, 3 Xianhui Bu, 4 Sue-Lein Wang 1 * The development of zeolite-like structures with extra-large pores (>12-membered rings, 12R) has been sporadic and is currently at 30R. In general, templating via molecules leads to crystalline frameworks, whereas the use of organized assemblies that permit much larger pores produces noncrystalline frameworks. Synthetic methods that generate crystallinity from both discrete templates and organized assemblies represent a viable design strategy for developing crystalline porous inorganic frameworks spanning the micro and meso regimes. We show that by integrating templating mechanisms for both zeolites and mesoporous silica in a single system, the channel size for gallium zincophosphites can be systematically tuned from 24R and 28R to 40R, 48R, 56R, 64R, and 72R. Although the materials have low thermal stability and retain their templating agents, single-activator doping of Mn 2+ can create white-light photoluminescence. Crystalline open-framework materials are of interest because of their rich structural chemistry and their use ranging from conventional catalysis, gas separation, and ion exchange to modern high-tech low-k materials, zeolite-dye microlasers, high-capacity H2 and CO 2 gas storage (1–4), and potential lanthanidefree phosphor materials for light-emitting diodes (5–7). Their functions are mainly attributed to properties related to pore size. Therefore, pore Supplementary Materials www.sciencemag.org/cgi/content/full/339/6121/807/DC1 Materials and Methods Figs. S1 to S3 References (34–39) 5 October 2012; accepted 12 December 2012 10.1126/science.1231160 REPORTS engineering goals such as enlarging the channels, changing channel shape and connectivity, or modifying the wall composition are critical for creating new materials. For many years, various zeolite-like structures have been synthesized using both simple and complex preparative techniques. In 1982, the discovery of AlPO4-based zeolite structures (8) inspired the synthesis of open-framework metal phosphates. Soon after, the crystal structure of an iron phosphate mineral known as cacoxenite (9) was solved, revealing that the structure contained notably large channels with a free diameter of 1.4 nm and openings encircled by 36 polyhedra (36R). These discoveries led to increasing interest in pure tetrahedral and mixed polyhedral frameworks with extra-large channels (table S1). Later, many landmark structures were synthesized 1 Department of Chemistry, Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University,Hsinchu30013,Taiwan. 2 Department of Chemistry, Chung-Yuan Christian University, Chungli 320, Taiwan. 3 Department of Chemistry, National Central University, Chungli 320, Taiwan. 4 Department of Chemistry and Biochemistry, CaliforniaStateUniversity,LongBeach,CA90840,USA. *To whom correspondence should be addressed. E-mail: slwang@mx.nthu.edu.tw Fig. 1. Systematic expansion of structures with extra-large channels. (A) Channel ring size ranging from 24R to 72R. (B) Pore diameters spanning the micro and meso regimes. The templates are alkyl monoamines (using a ball-and-stick model) with carbon chain lengths ranging from 4C to 18C. www.sciencemag.org SCIENCE VOL 339 15 FEBRUARY 2013 811 on February 14, 2013 www.sciencemag.org Downloaded from
REPORTS 812 (10–18), including SU-M, NTHU-5, and ITQ-37 (18), in which the upper limits of the channel sizes were delimited to 14R in aluminosilicates, 24R in phosphates, 26R in phosphites, and 30R in germanium oxides and germanosilicates. Relative to the more recent metal-organic frameworks Fig. 2. The structures of the family NTHU-13. (A) Three common building blocks. (B) Sequential linkages of blocks A, B, and C to yield varied channel edges and wall structures. (C) Schematic drawings showing channel expansion from 24R to 40R, 56R, and 72R with the growth of one or more BC pairs as the proliferation unit. Fig. 3. Periodic variation in symmetry accompanied by channel expansion via the insertion of BC pairs. The formulae for the channel walls, from left to right, are [A(BC)nBA], n =0,1,2,and3. Table 1. Compositions, cell lengths, channel edge connectivity, and porerelated data for the family NTHU-13. The monoamine templates are named according to the number of carbons of the straight-chain amine skeletons. Channel opening refers to the maximum size of a sphere that can fit into the opening (the estimated free diameter); the value in parentheses is the length of Code Template Framework a (or b) (Å) c (Å) 24R* 4C´ [GaFZn2(HPO3) 4] 2– 28R 6C´ [GaFZn7(H2O) 4(HPO3) 10] 4– 40R 8C´ [Ga2F2Zn9(H2O) 4(HPO3) 14] 6– 48R 12C´ [Ga4F4Zn23(H2O) 12(HPO3) 34] 14– 56R 14C´ [GaFZn7(H2O) 4(HPO3) 10] 4– 64R 16C´ [Ga4F4Zn33(H2O) 20(HPO3) 46] 18– 72R 18C´ [Ga2F2Zn19(H2O) 12(HPO3) 26] 10– *The structure is a Ga analog of NTHU-5 (17). (MOFs) (19, 20), progress in the expansion of inorganic channels has tended to be slow and accidental, without any way to predict the next channel ring size. This difficulty could be attributed to the lack of tunable spacer units (e.g., organic linkers) and an inability to control the linkages of the inorganic units; although certain germanates have been found to form from modular units (21, 22), neither their presence nor their topologies are predictable prior to the syntheses. In addition, limitations in channel or pore size may result from the fact that organized assemblies such as surfactantbased templates, while capable of creating large pore sizes, generally lead to disordered wall structures as exemplified by the mesoporous silicates. Thus far, the rational design of microporous and mesoporous inorganic frameworks with ordered wall structures has not been reported. Previously reported microporous structures have been primarily produced via template-directed routes under common hydrothermal or solvothermal conditions; however, the micropores or channels have not been manipulated using any specific type of discrete template molecule. Surfactanttemplated reactions provide a rational basis for the synthesis of various mesoporous materials (23, 24) in which long carbon chain surfactants with ammonium head groups aggregate into mesoscale template assemblies surrounded by amorphous inorganic walls (25). We report a systematic synthetic method that allows the production of extra-large channel inorganic frameworks based on gallium zincophosphites and referred to as NTHU-13. A series of aliphatic monoamines with straight carbon chain lengths ranging from four carbons (4C) to 18C were used as templates to enable channel expansion from 24R to 28R and then to 40R, 48R, 56R, 64R, and 72R (Fig. 1). Previous efforts that used monoamines with long straight carbon chains (>8C) in microporous material synthesis often led to lamellar-phased products. We found that we could increase the likelihood of larger channels by using heterometal centers. In single-metal systems, an increase in template size led to dif- the second dimension for a noncircular channel window. SAV [solvent-accessible volume (28)] is an estimate of percent unit cell volume not occupied by inorganic frameworks. FD is framework density. Dc is the density of alkyl monoamine templates within channels versus the density (D a) in a pure liquid state. V a is the total amount of molecular volume occupied by amine templates in a unit cell. Wall stoichiometry n Channel opening (nm) SAV (%) FD D c/D a V a/SAV 31.072 10.029 ABA 0 0.69 52.1 11.72 0.78/0.74 0.586 52.175 10.023 ABCb — 1.01 51.7 10.56 0.78/0.77 0.582 48.393 10.000 A(BC)BA 1 1.52 61.7 8.54 0.72/0.78 0.530 48.500 10.054 [A(BC)BA] 1 1.55 66.2 7.55 0.80/0.81 0.592 66.316 (b) [A(BC) 2BA] 2 (2.47) 66.310 9.982 A(BC) 2BA 2 2.52 70.5 6.56 0.73/0.78 0.540 84.043 10.036 [A(BC) 3BA] 3 (3.53) 72.3 5.94 0.71/0.78 0.525 66.298 (b) [A(BC) 2BA] 2 2.62 84.115 10.069 [A(BC) 3BA] 3 3.50 75.7 5.28 0.66/0.86 0.488 15 FEBRUARY 2013 VOL 339 SCIENCE www.sciencemag.org Downloaded from www.sciencemag.org on February 14, 2013
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